
The invention relates to a thermally insulating housing with two housing shells that are arranged one inside the other, that are at least largely vacuum-tight, that are spaced apart from one another by a thermal insulation layer, and that are connected to one another in a vacuum-tight fashion. The housing bounds in a thermally insulating fashion a useful space which is accessible through a loading opening.
In household appliances whose thermally insulating housing is based on vacuum insulation technology, the prior art joins together the vacuum-tight boundary walls, which serve as top layers, in wall pieces that are usually produced from stainless steel plate. The individual pieces are typically welded to one another. In this known manufacturing technology, the boundary walls are produced using a plate construction method, the individual wall sections being produced as planar sheet-metal blanks and welded to one another.
Furthermore, in the context of housings for domestic refrigerating appliances which are thermally insulating and are based on vacuum insulation technology, it has been known to assemble the boundary walls of the housing, which walls serve as the inner and outer enclosures, from preshaped profile sections that connect a plurality of wall sections to one another in one piece. Here, in each case one section which is formed in a U or L shape is used for one of the boundary walls, the base, the top and one side wall being produced by the U section and the rear wall and a further side wall being produced by the L section. In order to manufacture the inner and outer enclosures, the two sections are either butt welded to one another or welded to one another along joining flanges which are specially provided for this purpose.
The two housing construction techniques have in common that cutting tools which are complex in terms of tool technology and are thus cost-intensive have to be used in order to be able to ensure that the individual elements which are necessary to manufacture the top walls are joined together and connected in a vacuum-tight fashion in the case of mass-produced housing structures. Nevertheless, in both construction techniques, in particular if the individual elements are butt connected to one another, it is not possible to entirely exclude the possibility of leaks occurring which adversely affect the vacuum insulation. In order to be able to avoid this problem with the construction concept comprising a U section and an L section, the procedure has been adopted of providing the sections with so-called joining flanges at their connecting joints. The sections are then welded to one another along the flanges. However, this results in a situation in which the joining flanges project into the insulation volume generated by evacuation, and not only impede the insertion of insulation material which supports the two containers with respect to one another but also adversely affect the thermal insulation capacity of the vacuum insulation by reducing the possible insulation width in their region. Furthermore, for the boundary walls which serve as inner and outer containers, such manufacturing techniques result in the problem that, owing to the abrupt junctions which result when the individual elements are joined together, the welding procedure cannot be carried out continuously over the corner region of the components to be connected.
It is accordingly an object of the invention to provide a thermally insulating housing, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which uses simple structural measures.
With the foregoing and other objects in view there is provided, in accordance with the invention, a thermally insulating housing, comprising:
an outer housing shell and an inner housing shell disposed inside the outer housing shell, the inner and outer housing shells being at least largely vacuum-tight, spaced apart from one another by a thermal insulation layer, and vacuum-tightly connected to one another;
the housing shells bounding, in a thermally insulating fashion, a useful space accessible through a loading opening defined by the housing shells;
each of the housing shells being a tubular element having a first opening vacuum-tightly closed off with a substantially vacuum-tight cover and a second opening and the tubular element of the inner housing shell being formed with a second opening defining the loading opening of the housing.
In other words, the object of the invention are satisfied by the production of the housing shells from a tubular element which is closed in a vacuum-tight fashion at one of its openings with a cover which is of at least very largely vacuum-tight design, while the remaining opening of the inserted tubular element serves as a loading opening of the housing.
By using tubular elements for constructing the housing shells, it is possible not only easily to produce various housing cross sections by using semifinished products, for example, but also to make a housing structure in which only the rear wall has to be positioned with respect to the tubular elements by using clamping and joining devices and welding it thereto. In this way, not only is the expenditure on tools reduced but also particularly the length of the welding seams is made smaller to the benefit of a significantly increased vacuum-tightness owing to the welding seam-less wall junctions of the tubular element. In addition, such a housing manufacturing technique makes cornered areas on the tubular element possible, as a result of which the welding procedure with the cover which serves as a rear wall of the housing shell can progress continuously. In addition, the use of tubular elements which are equipped with radii in their corner regions makes it possible to use a connection section whose section elements which have to be inserted into the corner region are produced in one piece, for example by shaping a planar sheet-metal blank.
In accordance with an added feature of the invention, the tubular elements have a rectangular (e.g. square) base surface, and the cover sealing the first opening is a shell cover.
The shell-like design of the cover which serves as a rear wall avoids an abrupt junction with the tubular element which would entail a certain degree of processing unreliability in terms of production technology, since when the shell walls are joined together with the walls of the tubular element the cover is positioned with sufficient accuracy with respect to the tubular element. As a result, the expenditure in terms of clamping and positioning is significantly reduced.
In accordance with an additional feature of the invention, the shell cover engages over free edges defined around the first opening of the tubular element and is vacuum-tightly secured to the tubular element.
This method of connection between the cover and the tubular element produces a so-called overlap joint which, owing to the wall thicknesses of the shell walls and of the tubular element walls one on top of the other makes it possible to connect the two components in a vacuum-tight fashion with a high processing speed, for example in the event that the tubular element and the covers are produced from stainless steel plate or steel plate with a corrosion-protected surface. The engagement of the shell walls over the free edges of the openings in the tubular element forcibly centers the rear wall with respect to the tubular element.
In accordance with an alternative feature of the invention, the shell cover is insertible into the first opening of the tubular element and is vacuum-tightly secured in the first opening.
As a result, a stepless surface on both tubular elements is easily produced, the stepless shape of the inserted tubular element significantly facilitating the process of filling the element with thermal insulation material, such as open-celled polyurethane foam or polystyrene foams, for example, while the stepless implementation of the external housing shell can serve without any postprocessing as a visible surface for the thermally insulating housing. If the shell edges are turned toward the free edges of the tubular element, the cover and the tubular element can particularly easily be connected to one another in a vacuum-tight fashion, for example by seam welding, if they are produced for example from a stainless steel plate or corrosion-protected steel plate.
In accordance with a further feature of the invention, the shell cover is formed with a stepped recess defining a machine space in the insulating housing. A shell cover is particularly suitable with regard to the machine space recess. The machine space which serves as a recess can be manufactured particularly expediently and particularly dimensionally rigidly in terms of production technology if the shell-like cover is produced by deep drawing a stainless steel plate or a corrosion-protected steel plate.
In accordance with again an added feature of the invention, the shell cover is formed by deep drawing a stainless steel plate or a corrosion-protected steel plate.
In accordance with again an additional feature of the invention, the tubular elements are formed by bending a stainless or corrosion-protected steel plate and by vacuum-tightly welding the free ends of the steel plate to one another.
Such a solution makes it possible to dimension the tubular elements differently from the standardized tubes, in particular in terms of the shaping in their corner regions. As a result, the procedure of welding a connection section, connecting the two tubular elements to one another in a vacuum-tight fashion on the loading side, to the tubular elements can be carried out continuously with high processing reliability and high processing speed.
With the above and other objects in view there is also provided, in accordance with the invention, a refrigeration appliance, which comprises a thermally insulating housing as described in the foregoing.
A thermally insulating housing of a refrigerating appliance can be manufactured in a particularly reliable way in terms of processing and yet cost-effectively with the thermal-insulating housing as claimed.
In addition, a housing of a refrigerating appliance which can be disposed of in a particularly environmentally friendly way with a high thermal insulation capacity is produced.
A thermally insulating cooker muffle of a household oven can be manufactured in an equally particularly reliable way in terms of processing, robustly and with a high processing speed. Such an oven muffle can not only be disposed of in a particularly environmentally friendly way but is also thermally insulating to a high degree.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a thermally insulating housing, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.